Regensburg 2004 – scientific programme

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AKB: Biologische Physik

AKB 50: Poster Session "Biological Physics"

AKB 50.22: Poster

Friday, March 12, 2004, 10:30–13:00, B

Stability of adhesion clusters under constant force: a stochastic analysis — •Thorsten Erdmann and Ulrich S. Schwarz — Max Planck Institute of Colloids and Interfaces, Theory Division, 14424 Potsdam

Cells in multicellular organisms adhere to the extracellular matrix and to other cells through two-dimensional clusters of transmembrane adhesion receptors, which usually have to operate under mechanical load. We present a theoretical model which allows to study the stability of multiple parallel bonds under shared constant loading. The dynamics of thermally activated bond rupture and rebinding is modelled by a one-step Master equation with an absorbing boundary for the completely dissociated state. For small forces and weak rebinding, mean cluster lifetime grows only logarithmically with bond number. For strong rebinding, this dependence becomes exponential, thus rebinding is a very efficient way to stabilise adhesion clusters. For intermediate forces, a small increase in force leads to a large reduction in mean cluster lifetime. This allows cells to switch the stability of cell-matrix adhesions by loading through the cytoskeleton.